A convenient and stereoselective synthesis of allylic sulfides

The fractional distillation of 0-(2-alkenyl or 2-cycloalkenyl) S-alkyl dithiocarbonates (xanthates) affords 2-alkenyl or 2-cycloalkenyl alkyl sulfides. The reaction involves the [3,3]-sigmatropic rearrangement of the xanthates to produce S-(2-alkenyl or 2-cycloalkenyl) S-alkyl dithiocarbonates followed by extrusion of carbon oxysulfide to give 2-alkenyl or 2-cycloalkenyl alkyl sulfides.     

Functionalized cyclopentanes via radical cyclizations using thiocarbonate derivatives as initiators and terminators

A radical-based cyclization is described that employs xanthates or cyclic thionocarbonates as initiators and allylic dithiocarbonates or allylic thiocarbamates as terminators.     

An unexpected synthesis of ketene monothioacetals

Some dithiocarbonates (xanthates) can be converted into ketene monothioacetals through extrusion of sulfur upon treatment with base and an alkylating agent.     

Generation and intermolecular capture of cyclopropylacyl radicals

[reaction: see text] Cyclopropylacyl radicals derived from S-cyclopropylacyl xanthates (dithiocarbonates) undergo intermolecular additions to olefins without loss of CO or ring opening. In the presence of a phenyl ring on carbon C-1 of the cyclopropane ring, loss can be made to occur in the absence of an olefinic trap. The adducts from the cyclopropylacyl radical additions are easily converted into enones by base-induced beta-elimination of the xanthate group.     

Synthesis and reactions of 3-cyano-6-methoxymethyl-4-methyl-2(1H)-pyridinethione

Nucleophilic substitution of the chlorine atom in 2-chloro-3-cyano-6-methoxymethyl-4-methylpyridine by mercapto group produces the corresponding 2(1H)-pyridinethione, alkylation of which by halogenated compounds in the presence of KOH proceeds regioselectively to form S-alkyl derivatives. Thorpe—Ziegler cyclization of S-alkyl derivatives, which contain an active methylene group, yields new 3-aminothieno[2,3-b]-pyridines.Kuban State Technological University, Krasnodar 350072, Russia, and N. D. Zelinskii Institute of Organic Chemistry of the Russian Academy of Sciences, Moscow 117913; e-mail: stud@issep.rssi.ru. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 337–341, March, 1999.     

A divergent approach to highly substituted benzothiepinones and to 2,3-dihydrothieno[2,3-b]thiopyran-4-ones

The radical addition-transfer of S-(2-fluoro-phenacyl)xanthates can be used to construct rapidly benzothiepinones, including libraries of complex aza-bridged derivatives, and highly functionalized 2,3-dihydrothieno[2,3-b]thiopyran-4-ones.     

Crown Ether Catalysis in the Synthesis of Xanthates

Xanthates (0,S-dialkyl dithiocarbonates) received much attention in connection with technological¹ and synthetic applications². Pyrolytic elimination of xanthates, called the Chugaev reaction, has been widely used as a method of dehydrating alcohols without rearrangement of carbon skeleton³.     

O,O-二烷基S-烷基(芳基)二硫代磷酸酯的异构化氯化反应——合成S-烷基S-烷基(芳基)二硫代磷酸衍生物的新方法

报道了合成S-烷基S-烷基(芳基)二硫代磷酸衍生物的一种便利的新方法。O,O-二烷基S-烷基(芳基)二硫代磷酸酯与三氯氧磷发生氯化反应的同时,伴随着P=S键异构成P-S键,生成S-烷基S-烷基(芳基)二硫代磷酰氯,在碱存在下进一步与各种亲核试剂反应,得到S-烷基S-烷基(芳基)二硫代磷酸衍生物。     

Preparation of trifluoromethylpyridine libraries

S-Alkylation followed by heterocyclization of trifluoromethyl-3-cyano-2(1H)-pyridinethiones was used for preparation of libraries of S-alkyl trifluoromethylpyridines and thieno[2,3-b]pyridines. The S-alkylation (in water--DMF mixtures) was successful for all 18 alkylating agents employed (yields typically > 50%). S-Alkyl derivatives were further converted to corresponding thieno[2,3-b]pyridines via heterocyclization in base conditions (yields > 65%). Structures of new compounds were elucidated by a combination of IR and 1H NMR spectroscopy and elemental analysis and were confirmed by means of single-crystal X-ray diffraction analysis.     

Synthesis of substituted thienothiazoles

The action of sulfur monochloride on 2-amino-3-carboxy-5-phenylthiophene or 2-amino5-phenylthiophene hydrochloride gave 5-phenylthieno[2,3-d]-2-thioniathiazole chloride, which is converted to the corresponding hydrate on treatment with water. Heating of the thionium salt or its hydrate with carbon disulfide in an aqueous alcohol solution of aklaki gave 2-mercapto-5-phenylthieno[2,3-d]thiazole, which under the influence of dialkyl sulfates or on oxidation with potassium permanganate in alkaline media is converted, respectively, to S-alkyl derivatives or a 5-phenylthieno[2,3-d]thiazole-2-sulfonic acid salt. 2-Sulfo-3-alkylthieno[2,3-d]thiazolium betaines are obtained by heating the latter with alkylating agents. 2-Hydroxy-thieno[2,3-d]thiazoles were synthesized by hydrolysis of thienothiazole-2-sulfonic acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 477–480, April, 1979.     

S-烷基O-芳基硫代磷酸衍生物的合成及其杀虫活性的研究

研究了O,O-二烷基O-芳基硫代磷酸酯与三氧氧磷的异构化氯化反应。由此生成的S-烷基O-芳基硫代磷酰再与亲核试剂(醇,酚,硫醇,硫酚,伯胺或氨)在缚酸剂存在下反应,合成了42种化合物,其中34种未见文献报道。本文还研究了这类化合物的杀虫活性。     

Superoxide Ion–Promoted Facile One-Pot Synthesis of O-Alkyl-S-methyl Dithiocarbonates from Alcohol Under Mild Reaction Conditions

Abstract

A new, mild, and efficient protocol for the one-pot synthesis of O-alkyl-S-methyl dithiocarbonates (xanthates) has been described in reasonably good yields from a variety of alcohols employing carbon disulfide and methyl iodide using superoxide ion at room temperature.

GRAPHICAL ABSTRACT     

The isomerization/chlorination of 0,0-dialkyl methylthiophosphonates with phosphorus oxychloride—a new convenient synthesis of S-alkyl methylthiophosphonic acid derivatives

A new method for the synthesis of S-alkyl methylthiophosphonic acid derivatives is reported. The chlorination of 0,0-dialkyl methylthiophosphonates 8 with phosphorus oxychloride proceeds with isomerization of the P=S to the P–S bond to give S-alkyl methylthiophosphonochloridates 9 , which react further with various nucleophiles in the presence of triethylamine to afford S-alkyl methylthiophosphonic acid derivatives 10 . Among them, several compounds 10 show excellent fungicidal or insecticidal activities. © 1995 John Wiley & Sons, Inc.     

Selective one-pot synthesis of trithiocarbonates, xanthates, and dithiocarbamates for use in RAFT/MADIX living radical polymerizations

[reaction: see text] We report a facile route for the production of chain transfer agents for reversible addition fragmentation chain transfer (RAFT) and macromolecular design via the interchange of xanthates (MADIX) polymerizations, via a one-pot reaction. 1,1'-Thiocarbonyl diimidazole (TCDI) undergoes controlled monosubstitution when reacted with secondary thiols or alcohols. The intermediate S/O-esters of imidazole-N-thionocarboxylic acid react efficiently with a range of primary thiols, alcohols, and amines to form asymmetrical dithiocarbonates, trithiocarbonates, and dithiocarbamates, respectively. The synthesis provides a facile approach to the controlled radical polymerization of vinyl monomers through the reversible addition-fragmentation chain transfer (RAFT) mechanism.     

Deoxygenation of alcohols employing water as the hydrogen atom source

Trialkylboranes (BMe3, BEt3, and BBu3) have been shown to mediate reductive deoxygenation reactions of O-alkyl-S-methyl dithiocarbonates (methyl xanthates) in which water or deuterium oxide functions as the source of hydrogen or deuterium. This method has proven versatile with regard to substrate scope and is capable of providing protio- or deuterioalkane products in high yields with excellent levels of D-incorporation. Ab initio calculations suggest that the trialkylborane-water complex possesses an unusually low O-H bond dissociation energy (73 kcal/mol) and support a radical chain mechanism for this process. Taken together, this report provides evidence for fundamentally novel and previously overlooked modes of reactivity for water and trialkylboranes of wide ranging importance in both theoretical and applied investigations.     

A new and rapid access to homochiral 2,3-dihydro-oxazolo[2,3-b]quinazolin-5-ones

Starting from homochiral 1,3-oxazolidine-2-thiones 1, a two-step sequence led to homotopic 2,3-dihydro-oxazolo[2,3-b]quinazolin-5-one derivatives 3. The sequence was developed and studied regarding its scope and limitations.     

Synthesis of substituted 2-alkyl(aryl)thio-3-cyanopyridines and 3-aminothieno[2,3-b]pyridines

The alkylation of 6-methyl-4-methoxymethyl-3-cyano-2-(1H)pyridinethione by halogen derivatives in the presence of KOH proceeds regioselectively with the formation of S-alkyl derivatives. By cathodic electrolysis of the thiols in the presence of 6-methyl-4-methoxymethyl-2-chloro-3-cyanopyridine, 2-arylthiopyridines are obtained. By Thorpe-Ziegler cyclization of 2-alkylthiopyridines having an ctive methylene group, 2-aminothieno[2,3-b]pyridines have been synthesized.Kuban State Technological University, Krasnodar, 350072. N. D. Zelinskii Institute of Organic Chemistry, Moscow 117913. Southern Branch of Association Rosvuznauka, Krasnodar, 350072. Translated from Khimiya Geterotsiklicheskikh Soedinenii, NO. 10, pp. 1432–1437, October, 1996. Original article submitted April 2, 1996; revision submitted August 20, 1996.     

Modular approach to saturated and α,β-unsaturated ketones

2-Fluoro-6-pyridinyloxy derivatives of 2-ethoxyvinyl carbinols react with radicals derived from xanthates by an addition-fragmentation pathway to give highly functionalized ketones after acid hydrolysis. 1,4-Diketones are readily accessible by this approach. α,β-Unsaturated ketones can be obtained by starting with geminal acetoxy xanthates prepared by addition of a simpler xanthate to vinyl acetate.     

Formation mechanism of furfuryl sulfides from o-furfuryl dithiocarbonates: density functional theory study for aromatic [3,3]-sigmatropic rearrangement

Density functional theory (DFT) calculations at the B3LYP/6-31G(d) and B3LYP/6-31G+(d) levels demonstrated that O-furfuryl S-alkyl dithiocarbonate (1) undergoes aromatic [3,3]-sigmatropic rearrangement to the energetically unfavorable S-(2-methylene-2,3-dihydrofuran-3-yl) S-alkyl dithiocarbonate (2'), which then rearranges to furfuryl alkyl sulfide (3) with COS extrusion to regain the aromaticity lost in the first step.     

Facile one-pot synthesis of S-alkyl thiocarbamates

We report a novel one-pot two-step synthesis of a variety of S-alkyl thiocarbamates. This method offers a two-directional approach making use of trichloroacetyl chloride, requires no complex starting material, incorporates a variety of substituents, and proceeds in high yields.